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[John D'Errico]

When you remove the question, you make the answer useless to anyone else who might want to ask that question. This is an insult to the person who bothered to waste their time to help you.

[Star Strider]

John — TMW will re-post the original if you request them to. Apparently they keep back-up copies.

Answer 1

[Mischa Kim]

Kenneth, check out and run this:

g       = 9.81;
L       = linspace(1,10,14);
theta_0 = 30;
for t = 0:0.1:60 %time in seconds
    theta =  theta_0*sin(sqrt(g./L)*t);
    x     =  L.*sind(theta);
    y     = -L.*cosd(theta);
    %creating a rope
    r     =  plot(x,y,'*');
    %creating a bob
    hold on
    b     =  plot(x(length(x)),y(length(y)),'or','markersize',30,'markerfacecolor','r');
    axis([-max(L) max(L) -max(L) 0])
    drawnow
    delete(r)
    delete(b)
end

Code needs to be cleaned up but I think you get the drift.

Also note that I changed your equation for theta to show the non-linear behavior of pendula.